A sculpture generally refers to a three-dimensional art work. Sculptures have been made in various materials. A particular type of sculpture can be referred to as bas-relief or low relief. In general, a bas-relief or low relief is a type of sculpture where the image projects from a background and has a shallow overall depth. Bas-reliefs or low reliefs are often prepared by removing background material, and examples of bas-reliefs are very common. Examples of bas-reliefs or low reliefs that are made by a technique other than removing background material include coins. Modern coins are typically prepared by stamping or coining.
There have been recent attempts to produce photographic images in relief in metallic materials such as bronze. While photographic images in relief can be considered a type of bas-relief or low relief, photographic images in relief are different because they are generated from a photograph or photographic image and are provided to mimic or replicate the photograph or photographic image, utilize a tight relief depth range, and provide shading corresponding to location in the relief depth to create a photographic look. Furthermore, photographic relief images are typically prepared in a “one-off” situation. That is, photographic relief images are typically not mass produced.
One area in which photographic images are introduced into a metallic material is the area of memorial products. One technique for introducing a photographic image into a metallic material involves utilizing a CNC machine to route an image based upon a photograph into the surface of a bronze plaque to create a memorial product. See U.S. Pat. No. 6,950,713 to Walthall. Other techniques involve using a CNC machine to route a relatively softer material that can be used as a pattern for creating a mold in sand, and then casting a bronze plaque using the mold. See U.S. Pat. No. 7,814,959 to Karenbauer and U.S. Patent Publication No. US 2008/0148539 to Shepherd et al. U.S. Patent Publication No. US 2008/0148539 to Shepherd et al. appreciate the desirability of providing a tight relief depth range and small relief depth in order to more closely mimic or replicate the photographic image. These techniques that utilize a CNC router are limited in their ability to achieve a resolution or crispness of image that corresponds to the smallest router bit that can be used to remove the material. When following these techniques that utilize a CNC router, one must compromise between the resolution or clarity of the image and the speed of the process. Using a very small router bit (for example, a router bit having a bit width of 0.0312 inch ( 1/32 inch) or smaller) may be impractical because of the length of time necessary to create the image in the bronze or pattern material. Furthermore, because the router bit contacts the bronze or pattern material, it is necessary to periodically sharpen or replace the router bit which contributes to additional expense. Even when using a router bit having a very small bit width, the resolution or clarity is still limited. Furthermore, the speed at which a router bit can route a surface is limited by considerations such as the stress and wear. Under too much stress, a router bit may bend resulting in loss of clarity. Furthermore, too much stress may cause a router bit to heat up and where out thereby requiring replacement or sharpening.
Lasers have been used to create sculptures. Often, the sculptures are in the form of signage. For example, see U.S. Pat. No. 4,126,500 to Palanos and US Patent Publication No. US 2003/0019135 to Luckenbaugh. Lasers have been used in sub-surface laser engraving. See U.S. Pat. No. 6,605,797 to Troitski. Lasers have additionally been used to create images as a result of pitting a material such as stone. For example, see U.S. Patent Publication No. US 2008/0160254 to Arnold. These pitted stone products, however, do not exhibit a relief depth sufficient to create a mold for casting a metallic material in order to provide the image on the cast metallic material.